arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2312.04735quant-ph
收藏

Trotter化误差对单粒子隧穿的影响

Influence of Trotterization error on single-particle tunneling

University Grenoble-Alpes(格勒诺布尔阿尔卑斯大学);Google Research(谷歌研究)

Anton V. Khvalyuk, Kostyantyn Kechedzhi, Vadim S. Smelyansky, Lev B. Ioffe

AI总结:

该研究表征了Suzuki-Trotter算法(STA)对单粒子隧穿的影响,发现STA保留目标共振时隧穿率指数增强,可降低超导量子硬件模拟隧穿的门数需求,为相关模拟提供了可控平台。

摘要:

现有超导量子设备难以模拟空间量子隧穿,因其呈指数级缓慢且具有内在非局域性。Suzuki-Trotter算法(STA)为现有量子硬件提供了实用解决方案,该算法通过局域两量子比特门序列近似非局域演化,无需辅助量子比特且保留物理可解释性。然而,基于朴素保真度的误差界估算所需门数会超过真实设备中噪声与退相干施加的约束。在此,我们通过适配Wentzel-Kramers-Brillouin近似,对半经典隧穿模型的STA进行了完整表征。我们发现,一般情况下隧穿会因共振失谐而被抑制;相反,若STA保留目标共振,隧穿率会通过非微扰重整化呈指数级增强,大幅降低观测隧穿所需的门数,从而得益于大Trotter步长——这对现有量子硬件而言同样自然。但对于后一区域,我们进一步发现准能级的Floquet混合会重构低能谱,并通过引入额外允许区域强烈变形隧穿动力学。基于半经典图像,我们推测在存在改变拓扑的修正(如交错势调制)时,隧穿与大步长STA会相互作用——这是未来的研究主题。我们的发现支持在现有超导平台上直接进行隧穿模拟,为研究隧穿与STA的非平凡相互作用提供了可控平台,也为探究噪声、无序与相互作用的影响提供了可能。

英文摘要:

Existing superconducting quantum devices struggle to simulate spatial quantum tunneling as it is exponentially slow and inherently nonlocal. The Suzuki-Trotter algorithm (STA) offers a practical solution for existing quantum hardware by approximating nonlocal evolution with a local two-qubit gate sequence that requires no ancilla qubits and preserves physical interpretability. However, estimating the required gate count from naive fidelity-based error bounds yields values exceeding the constraints imposed by noise and decoherence in real devices. Here, we fully characterize STA for a semiclassical tunneling model by adapting the Wentzel-Kramers-Brillouin approximation. We find that, in the general case, tunneling is suppressed by resonance detuning. In contrast, if STA preserves the target resonance, tunneling rates are exponentially enhanced via non-perturbative renormalization, dramatically reducing the gate count required to observe tunneling and thus benefiting from large Trotter steps$\unicode{x2013}$equally natural for existing quantum hardware. However, for the latter regime, we further find that Floquet mixing of quasi-energy levels reconstructs the low-energy spectrum and strongly deforms tunneling dynamics by introducing additional allowed regions. Based on the semiclassical picture, we conjecture interplay of tunneling and large-step STA in the presence of topology-altering modifications, such as staggered potential modulation$\unicode{x2013}$a subject of future work. Our findings enable direct tunneling simulations on existing superconducting platforms, providing a controlled platform for studying the nontrivial interplay of tunneling and STA, with the possibility of addressing the effects of noise, disorder, and interaction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑